Types of relationships

Your tables can participate in three types of relationships, and the picture shows them.

You have a one-to-one relationship when a single record in one table is related to a single record in another table, and vice versa. For example, one specialized file server may have just one repair technician.

You have a one-to-many relationship when one record in a table is related to many records in another table. For example, one employee can use many assets, such as a computer, chair, and desk.

You have a many-to-many relationship when several records in one table are related to several records in another table. For example, your company probably owns a large number of computers, and you may use several technicians to maintain those computers. Many technicians can be responsible for many computers.

This course shows you how to create all three types, but we’ll spend most of our time on one-to-many relationships because they’re the most common. Also, if you want to publish a database to SharePoint, then you have to create lookup fields, and a video later in this course shows you how.